1. Technical Field
This invention in general relates to semiconductor circuits and flat panel display modules. More specifically, this invention relates to circuits for driving columns of organic light emitting diode (OLED) displays.
2. Description of the Related Art
An organic light emitting diode (OLED) display is made up of rows and column electrodes for selectively activating the OLED device at each intersection. FIG. 1 shows a conventional single scan driving scheme where an OLED panel 10 is driven by a row driver 11 that drives row electrodes an a column driver 12 that drives column electrodes. The row electrodes are scanned in sequence to refresh the display image.
As the OLED display becomes larger with an increased number of row electrodes, the resistance of the column electrodes increases, which, in turn, increases the power dissipation along the columns.
There is a dual scan scheme where a flat panel display is divided into two parts, an upper panel and a lower panel, and there are two column drivers, each of which is responsible for driving each half panel. The dual scan scheme helps reduce the power consumption by reducing the resistance of column electrodes by 50%. However, the dual scan scheme has the problem of non-uniformity of brightness across the boundary between the upper and lower panels.
Therefore, there is a need for a new single scan scheme that can drive an OLED display with less power consumption without dividing the panel.